Adjustable electromagnetic unit



Jan. 1 1929 3,697,323

. S. W. M KELLIP ADJUSTABLE ELECTROMAGNETIC UNIT Filed April 8, 1.926 2 Sheets-Sheet 1 INV NTOR:

ATTORNEYET Jan. l,' 1929. 1,697;323

s. w. MOKELLIE ADJUSTABLE ELECTROMAGNETIC UNIT Filed April 8, 1926 2 s eets-sheet 2 M, 2/ E NVENTOR:

v BY

Patented Jan. 1 i929.

UNHTED @TATES mamas ale-rear caries,

SPENCER W. MOKELLIP, F PHILADELPHIA, lENNSYLVANIA, ASSIGNOR TO WIRT COIM PANY, OF GERMANTOWN,' PENNSYLVANIA, A CORPORATION OF MAINE.

ADJUSTABLE ELEC Application filcdApril 8 or similar material upon which are mounted 1 5 the various parts of the unit, whereby the vibration set up in the vibratory members of the unit tend to be confined or limited to said base member and are not absorbed or transferred to parts of the unit, which are not intended to vibrate, said base having fg n'rounted thereon the two'coil'supports, in the center of, or between which, is theelec- -tromagnetic coil having a hollow core;

The permanent magnet, used to create a 'magnetic field is clamped to the two coil supports, and the four tached to the sides of t e coil supports in sucha manner that when the milled ends of;

ole pieces. are atsaid pole pieces overlay one, another with a gap in between, all four are the direct /ported at its inner or bottom end but free to vibrate at its upper end, said armature being held in its proper positiorr between thin plates carried by a screw passing througha tubular post or spacer and supported from. the hard rubber base aforesaid. The post or spacerv is so positioned as to permit the outer or free end of the armature to pass through the gap between the four pole pieces "My invention further consists of a simple and direct means, whereby the vibrations set up in the armature or main vibratory member of said unit are directly transferred or carried to'a tympanum, diaphragm, cone or other suitable sound regenerating or sound reproducing member, to produce sound waves, by a light spring wire, or reed, attached directly to the armature itself, and extending therefrom in opposite directions to said sound reproducing member and to suitable adjusting devices respectively.-

TROMAGNETIC UNIT.

, 1926. Serial No. 100,662.

. In a unit of this general character aforesaid which creates a double push and pull action on the armature, due to the'reverse I position of the pole pieces, the strongest vibrations .can be obtained where a permanent magnet is used, and'when the armature is I placed directly in this powerful magnetic field, as is the case in my novel unit, there is naturally a decided tendency for the, armature .to be deflected or drawn to either one side or the, other. Of courseif the armature is'allowed to h-it or contact with one of the pole pieces the rate of its vibratory efliciency is impaired, and vin order to create the best effects it is desirable for the armature to float in the gap between the poles, or in other words, to be in proper magnetic balance between said poles. If the armature is'constructed' of material: thick enough so that it has enough rigidity within itself to overcome the magnetic pull either one way or the other and hold' a magnetic balance itself, I have found that the vibrations are not of the same intensity at various freuencies and' also that the vibrations over cut down-or reduced, whichywhen the unit is connected to, a suitable tympanum, 'diaphragm, cone or the like would have a tend- ;ency to deteriorate or cut down the volume of, sound produced by such an organization. In other words I find that to produce a'maximum amount of vibration with a given amount of pulsating electrical energy being fed through or impressed upon the electromagnetic coil, that the armature should be preferably constructed of light, soft, iron held in its proper position or in magnetic. balance between the poles of said unit and further that the method or means employed for holding the armature between said poles should still allow the armature to vibrate freely and not have a dampening eflect thereon. My novel construction not only accomplishes the foregoing ends but. also further allows or provides for a manual adjustment or moving of the armature in the gap between the poles.

To the above ends my invention consists of a novel manner of mounting and adjust ing the armature in a unit of this character, said armature having its inner end fixedly supported with its outer end free to vibrate, andv having a reed passing therethrough and brazed thereto, sald reed having one end tent of said manualadjustment;

connected to a Sound-regenerating or repro- It further consists of a novel manner the'armature' adjusting mechanism, and a novel manner ofmounting and collocating the coil, the permanent magnet and their v adjuncts. v

It further consists of a novel manner of collocating thereed andarmature, andanovel means for effecting thesimultaneous' adjustment of botlisaid reed and armature.

It further consists of other novel features ofconstruction and; advantage, as will beQ hereinafter pointed out in the specification 12 above referred to. The upper ends of and claims appended hereto.

For the purpose of illustrating my inven- -tion I have shown in the accompanying drawings the form thereof which is atpresent preferred by me, since the 'samehas been. found in practice to give satisfactory and reliable results, althoughit islto be understood that the various instrumentalities of the manner'of connecting the'reedwith the which my invention consists can be variously arranged'andorganized and that my finvention'is not limited to-the. precise arrangement and organization of the instrumentali-.

ties as herein shown and described;

Figure 1, 1s a vertical sectional vlew of an ad ustable electro magnetic unit embodying my'invention'the section being taken on line 1 1 Figure 2, certain of the parts being sition thereonby the outer lock nut 23.

shown in elevation. F1gure2,is aplan view of the device.

Figure 3, vis-a rear elevation of the device. Figure 4, is an enlarged view similar to, F 1g. 1 showing the c011 insect on.

Figure 5; is aperspective View. showing armature and its adjuncts, and my novel adjusting. mechanism therefor, certain parts beingomitted for clearness of illustration.

Similar numerals offrefer'ence ind cate corresponding parts;

My novel adjustable electi e-magnetic unit indicated generally by 1 is connected by means of a bindingscrew 30 to a loud speaker or acoustic device indicated by 2, and

' comprises t-he coil 3 having the armatureor -v1 bratory member 4 passing therethrough reed and armature being brazed together or pole pieces.

which is attached to the member 2 by, a connecting element such as a pin or reed 5, said otherwise rigidlyconnected at the point 6 so as to form a "unitary structure, as 'will be understood from Figures 4 and 5.

7 designates'the coil supports of iron or steel carrying the pole pieces 8, and to which,

is attached the 'base 9 of suitable. insulating material, as hard rubber or the like, or 1t may be'made of brass or other nonmagneticmaterial, 10 is the permanent or' horse shoe magnet which is supported by the Y magnet clamp 11. 12 designates the spacing sleeve surrounding the bolt or armature support.18, 13 the termial block, and 14 the unit 7 support by which it may be connected to a of mounting and supporting the'armature and [is-loo ed or held permanently as will be hereinafter explained, and as, best seen ins-0 Figures 4 and Y.

18 designates a bolt which passes through the-lower end of thearmature 4 which latter has the-thinlplates 19 on each side'thereof,-

.said bolt passing through the spacing sleeve the plates 19 are extended-upwardly a short distancein' proximity to the armature as indicated at 20, (see Figures 4and 5) which construction has a stabilizing effect on the armature 4, one of saidplates 19 being held between the head of said bolt. and the lower end of-said armature While the other of said plates is held between the opposite wall of said armature and'the' contiguous end of the spacing sleeve 12. The bolt 18 after passing through the sleeve or spacing member 12,

passes throughthe Washer 29 and base '9, and

as on its outer end the washer 21 and the inner lock nut 22, the outer end of said bolt 18 passingthi'ough the lower end of the bar 17, which latter is locked or secured in pc- By, tightening. the nut 23 which has a flat surface next to the resilient, stabilizing, control and adjusting bar '17, the lower end ofthela'tter is rigidly and immovably held in fixed position,'while the upper end thereof is slight extent, 'as will be hereinafter explained.

The adjusting screw 24 which is threaded latter is locked with respect to said adjusting screw by the inner and outer lock nuts 26.

capable of being flexed or adjusted to a.

which are tightened against the bar 17 so I i that when the latter is rotated in the base 9,

there is a slight but adequate lateral move-- "ment imparted to the upper end of the bar 17, so that the armature 4 simultaneously adjusted to position it centrally between the pointer or finger 27, the movement-of which in either direction is limited by the nuts 28 of the clamping bolts, common to the mem- Carried on the screw 24 isja' bers 9 and 14, whereby said finger27 acts as a stop to limit the extreme, movement in either direction of the armature 4 and bar: 17, beyond the approximate desired position of the armature 4 with respect to the gap between the pole pieces 8.

The armature 4 is helped in maintaining its magnetic balance by the two thin leaves 19 on opposite sides of its lower end, and the whole armature assembly consisting of the thin plates 19, armature 4, tubular post or r space-r 12 and the washers 29 and 21 are locked or held to the base 9 by the screw or bolt 18, which passes through all said mem bers including the base and is drawn tight and held in place by the lock nut 22. This screw 18 is made sufiiciently long to also passthr'ough the thin bar 17 which is made of spring brass, bronze or other suitable material and is placed directly between the lock nuts 22 and 23.

The reed or connecting member 5 which I use to transmit the vibrations from the armature to a diaphragm or acoustiomember 2,"to produce sound waves, is preferably attached to the armature 4, adjacent the lower pair of the pole pieces at the bottom of coil 3 so that a considerable movement is imparted to said reed which results in a maximum intensity of vibrations being transmitted through the reed to the diaphragm.

The armature 4 is held fixed at its inner end, and vibrates in the gap between the poles 8 and the reed being brazed directly as at 6 in a position at rightangles to the armature, it will be apparent that when the armature 4 moves from side to side, the reed will not only have a' longitudinal movement, but a slight up and down movement at its point of attachment. This vertical movement, though slight, is augmented at the free end of the reed or pin, the amount of amplifica-I tion of movement of course depending upon the lengthof the pin and its rigidity. The

outer end of the pin is attached to the acoustic element 2, and in order therefore to pre-' vent the latter-from dampening or retarding the movement of the armature and to transmit' from the armature to said .lements all the armature vibrations I use a light springy reed-5 which will flex to a certain extent and will allow the armature 4 to vibrate freely.

I have found from extensive experiments that it .isessential in transmitting this maximum vibration to the diaphragm 2 that the vibrations set: up in the armature 4 be carried in as direct a manner as is possible to said diaphragm. There should be nothing to interfere-.with this transmission of vibration, which is effected by my novel construction, since the reed 5 while fastened to or brazed to the armature 4 also passes through the latter, also through the opening 16 is the base 9 and, terminates 'or is fastened to the front end of the thin springy bar 17 which is fastened to and against the armature assembly by the lock nut 23 on the end of the bolt 18. By this formation I produce a light, rectangular, continuous, vibratory assembly, wherein the armature '4 and the upper end of the bar 17 form two parallel sides of the rectangle and the connecting end or extension 31 of the reed, the tubular post 12 and the inner end of the screw 24 form the other two parallel sides. The threaded stem 24 passes through the center of the resilient bar 17 at a point approximately half way betweenthejunction of'the reed therewith and the inner e'nd'positioned be- I tween the lock nuts 22 and 2 3 and can be rotated freely to a limited extent. .The

front end of the stem 24 being threaded into the rubber base 9 of the unit, it-will be seen that when said stem is turned in either dithe armature 4 is likewise moved, due to the reed 5 connecting therewith. The bar 17 is of resilient,-vibratory metal of the proper width and-thickness, so that it will along with the stabilizing plates 19 at the fixed end of the armature 4 assist the latter in maintaining a state of magnetic balance and in case of a blow on the diaphragm or if for.

any other reason the armature shouid con-' "r'ection the bar 17 is moved laterally and y tact with a pole piece 8, it can be manually 'moved' by theknob 25 back to the proper position as seen in Figs. 1, 2, 4 and 5 and practically held in a point of magnetic balance without materially affecting the intensity of vibration.

It will be apparent from the foregoing that my novel. unit will produce for and transmit to a desired sound reproducing tympanum or diaphragm of any description, the maximum amount of vibration with the least amount of loss, and I have further be cheaply manufactured, since nearlyall' the elements can be cut to the desired lengths from small rods, bars, tubes and the like, and readily and expeditiously assembled.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is: v

1. In a device of the character stated, a coil, an armature therefor passing through said coil and having its inner end fixedly supported, a reed secured directly to said armature passing therethrough and movable in unison therewith,-a resilient bar attached to said reed and an adjusting device forsaid barn v 2. In a device of the character stated, the

combination of a coil, upper and lower pole pieces therefor, an armature passing through said co l and fixed at one end but free to vibrate at the. other end, a flexible bar par to said armature, and a reed having one end I site portions-fast leading to a-sound reproducer and its oppoto said armature and to 7 said bar.

4. The combination of 'a-coil, upper and lower pole pieces therefor, an armature passing through said coil and between said pole pieces, afixed support forbne end of said armature, the'other end of said'armature being free to vibrate, a flexible bar parallel to said armature and a reed having one end leading to a sound reprodueer and its opposite portions fast to said armature and to said bar, and means for adjustin said bar and armature in unison.

5. The combination of coil, upper and lower pole pieces therefor, an armature pass-- ing through said coil and between said pole pieces, a fixed support for one .end of said armature, the other .end thereof being free.

to vibrate afiexible bar parallel to said armature, and a reed having one end leading 'to a sound reproducer and its other end fast to said armature and to said bar, and means for adjusting said bar, armature and reed in unison.

' are simultaneously adjust-able and means for limiting the movement of saidadjust ,6. The combination of an insulating base, a coil, an armature fixed at one end thereof, a reed passing through said armature and fast thereto and having one end adapted to be connectedto a sound reproducing ele "ment, a resilient bar to which the other end of said reed is connected, an ad uStmg screw passing through'said plate and threaded into said base whereby said reed and armature.

ing device.

7 In a device of the character stated, the combination of an insulating-base, a co l,

upper and lower pole pieces therefor.- an armature passing through said coil and fixed "at one end but free to vibrate at the other end, a flexible bar parallel to said'armature and connected thereto,'a' reed fast to said ing'through the lower end of said. armature, 3

armature and bar, an adjusting screw threaded into sa d base for ad]ust1ng said bar and armature. 1n unison, and a bolt pass and said bar-and base. p

8. The combination of a base, a 0011, upper and lower pole pieces therefor, an armature passing through said coil and between said pole pieces, a bolt passing through the lower end'of said armature, the other end of said armature, being free to vibrate, a flexible bar parallel to said armature, and having its lower end carried by said bolt, a reed having one end leading to asound re producer and its opposite portions fast to said armature and to said bar, and an ad jnst'ing screw; threaded into said base and passing through said flexible bar and being fast thereto.

9. The combination of a'base, a coil,

per and lower pole pieces therefor, an ar-. mature-passingthrough said 0011 and between said-pole pieces, a bolt passing through the lower end of said armature, the totherend ofsaid armature'being free to vibrate, a

flexible bar parallel to said armature and supported on said bolt, a reed having one end leading to a sound reproduc'er and its opposite portions fastto said armature and a. spacing sleeve intermediate said armature and base. i I

10. In a device of the character 'deframe, an electro-magnetic coil thereon havinga pole piece and an armature hav ng a free end ad acent the pole piece and its opposite end attached to'the -frame, of, a sta- 'bilizer attached to theframe' having a free end extending parallel to; and in spaced re-' lation-to thefree end of the armature, a rigid connection. between the stabilizer and armature at a distance away from their attached ends, and a. vibrationtransmitting member attached to said armature.

1-1 In a device of'the character described,

the combination with a frame, an electromagnetic coil mounted thereon havinga' pole "piece and an armature attached tothe frame at one side of the coil and having'its free vend extending into" juxtapositionwith the pole piece, of a stabilizing vibratory'mem;

ber rigidly attached to the'frame and having its free end-extending in parallelism with the farmature, arigid connection between the vibratory parts of the I armature.

scribed, the combination-with a supporting and stabilizing member, means for adjust- ,ing thelatter to vary'the position 'of'the armature with reference to the pole pieces, and a vibration transmitting member,at-

tached to the armature.

I 12111 a device of the character described,

the combination with a 'yibratory armature andstabilizei" spaced apart and each rigidly supported at one end, and a rigid connection between them at a distance from their attached ends, of aframe supporting said ele-' ments, means cooperating with the. frame and stabilizing member for moving its free end .and the freeendiof the armature laterally,-a pole piece on the'frame: cooperating with the armature and a vibration transmitting member attached to the -armature.

13. In a device of the character described,

' the combination with a permanent magnet having parallel extremities spaced apart, ,a frame embracing said extremities compris- 5 ing spaced pairs of pole pieces extending to- Wards each other from each oi the extremities of the permanent magnet, thepole pieces of one polarity overlapping those of the otherpolarity, and also -spaced there 10 from, of an electro-magnetic coil located in the space between the overlapping ends of the pairs of pole pieces and having an aperture therein and an armature having one end fixedly secured at a distance away from said pole pieces and having its vibrating end portion extending between each spaced pair of pole pieces.

In testimony signed my'name.

SPENCER W. MCKELLE.

whereof, I have hereunto 

